Process for lowering the pour points of mineral oils



Patented Mar. 9, 1937 UNITED STATES PATENT OFFICE PROCESS FOR LOWERING THE POUR POINTS OF MINER-AL OILS Adrianna Johannes van Peski, Bussum, Netherlands, assignor to Shell Development Company, San Francisco, Calif., a corporation of Dela.- ware 'No Drawing. Application August 2 1933, Seria5l I No. 683,298. In the Netherlan 9 Claims.

obtainedby hydrogenation, may show a large increase of viscosity upon the temperature being lowered. The viscosity may even be increased to 10 the extent of rendering the oil entirely unpourable. This so-called congelation of the lubrieating oil isto be ascribed to the crystallizable paraflin wax present therein. At a low temperature this paramn'wax forms a needle-like structure in the oil, with the result that the latter loses its fluidity. It is evident that lubricants having this property cannot be used in engines operating at low temperatures.

Various-methods have already been proposed to separate the crystallizable paraffin wax from the oll. It is known to freeze the oil, sometimes after the addition of solvents, and subsequently to filter off the crystallized paramn wax by means of filter-presses or centrifuges. It is further known to prevent the crystallization of paramnwax at low temperatures by the addition of small or large quantities of special substances, known as pour point reducers.

It is already known to reduce the pour point of lubricating oils by adding thereto small quantities of a product obtained by coupling highly molecular parafdnic hydrocarbons to aromatic hydrocarbons, such as naphthalene, anthracene, or benzene.

It has now been found that pour point reducing agents of greater power than those formerly known can be obtained by using for their manufacture highly condensed cyclic hydrocarbons of compound cyclic structures instead of the simple 4 aromatic hydrocarbons mentioned above. These highly condensed cyclic hydrocarbons may be found as naturally present in certain materials, in which case such mixtures may be used, if desired, as initial stock material for the coupling .-reaction with high molecular parafilnic hydro- I carbons. The following are examples of materials containing highly condensed cyclic hydrocarbons, viz. high boiling Edeleanu extracts or polymers thereof, cracked high boiling distillates 50 or residues. The latter materials contain, inter alia, crackene, a highly condensed aromatic hy-- drocarbon, which when coupled to one of the higher parafilnic hydrocarbons yields a product .with a strong pour point reducing action. Liquid materials of the type of Edeleanu extracts and August cracked residues may be regarded as solutions of aromatic hydrocarbons.

The highly condensed cyclic hydrocarbons can also be obtained by subjecting cyclic and particularly aromatic hydrocarbons with or without side 5 chains (partly. or completely hydrogenated, if desired), substituted or not, or derivatives thereof, such as alkyl-aryl, oxy-aryl, or other similar compounds, their homologues and/or analogues,

or solid or liquid mixtures containing these sub- 6 stances, to a heat treatment in the presence or absence of condensing agents. A few examples ;of substances which can be worked up into the desired highly condensed cyclic hydrocarbons are: benzene, naphthalene, anthracene, phenan- 15 threne, tetraline, dihydroanthracene, methylnaphthalene, fluoranthene, chrysene, retene, their homologues and hydrogenation products. It is, however, also possible to start with mixtures or solutions containing these or. similar substances, such as Edeleanu extracts, obtained by the treatment with' liquid S0: or vkerosene or heavier petroleum distillates, such as lubricating oil distillates, or corresponding cracked fractions, or heavier residues; also certain tar-oil fractions may be used.

If necessary, metal halides, such as aluminium chloride, zinc chloride, ferric chloride, boron fluoride and the like, may be used as condensing agents.

In general not much is known with certainty as regards the-constitution of the products obtained by condensing the above types of cyclic organic compounds. The product obtained, for example, by heating naphthalene with aluminium chloride, according to Homer and Purvis, is tetramethylpicene (vide J. Chem. Soc. 93, 1325, 1928).

The highly condensed cyclic organic compounds may be coupled, or condensed, with a parafllnic hydrocarbon, or a mixture of such hydrocarbons, 40 by any known method, such, for example, as one of those described by Sabatier inhisflatalysis in Organic Chemistry, Chapter XX.

The products obtained by condensation of highly condensed cyclic compounds with high molecular paraflinic hydrocarbons can b'subjected to an extraction treatment with selective solvents whereby a separationinto'active' and inactive constituents is effected.

For the purpose of illustrating the manner in which the invention can be carried out in practice, the following examples are set forth: 1. An Edeleanu extract with S. F. viscosity of 36 seconds at 25 C., btained by treating spindle oil, was heated with ab t 10% anhydrous ZnClz at about 250 C. for about 4 hours at atmospheric pressure. The condensation product, rich in highly condensed aromatics, was separated from settled sludge, washed with water and then dried.

Chlorinated parafiin wax prepared in a conventional manner and containing 14.8% C1 was used as a source of parafiinic: radicles to be coupled onto the condensed aromatic nuclei. This coupling was carried out by heating 15 grams of the above condensation product with 40 grams of the chlorinated paraflin wax, at 50-60 C. for about 24 hours in the presence of anhydrous AlCls and about 50 cm of carbon bisulphide. Thereafter the product was separated from the sludge, washed with water and lye and then the constituents boiling below 300 C. were removed by steam distillation. The product thus obtained, when added in a quantity of 0.3% by weight to a Pennsylvania oil having a pour pointof 0 C., lowered the pour point by 15 C.

2. Picene was prepared by heating 3 parts by weight of napththalene with 1 part by weight of aluminium chloride during 10 hours at C., diluting the resulting product with benzene, washing with iced water and eliminating the benzene and non-converted napthalene by steam distillation and small quantities of formed dinaphthyl by distillation in vacuo until the temperature of the liquid is about 270 C. at a pressure of 10 mm.

A condensation product of picene with 3 mol. of chlorinated paraffin wax was obtained by stirring 20 grams of picene with 60 grams" of chlorinated paraflin wax and 20 grams of AlCls in cm of kerosene during 24 hours at room temperature,- allowing the temperature to rise slowly to about 90 0., Washing out with water in order to eliminate the AlCla and removing the excess of kerosene and paraflin wax by distillation in a current of nitrogen (in order to exclude the influence of oxygen). When adding 0.5% of the resulting product to a Pennsylvania turbine oil, having a pour point of 0 C., a pour point reduction of 5 C. is obtained. When addiligg 2% the reduction amounts to more than A product prepared in exactly the same manner by condensation of 1 mol. of napththalene with 3 mol. of chlorinated paraflin wax, when added in a quantity of 0.5% to the same Pennsylvania oil did practically not lower the pour point; 2% gave a pour point reduction of 1 C.

3. A condensation product of picene with 2 mol. of chlorinated paraifin wax was prepared by heating 20 grams of picene with 40 grams of chlorinated paraflin wax and 20 grams of A1613 in 50 cm CS2 during 15 hours at 50-60 C. whilst using a reflux condenser. 0.5% of the resulting product, when added to a Pennsylvania turbine oil, gave a pour point reduction of 9 C. After removing the excess of paraflin wax by distillation, as described in Example 2, 0.5% gave a reduction of 21 C. By extraction with butanone 15 grams of the product was separated into 9 grams insoluble in butanone and 6 grams'soluble in butanone. 0.5% of the insoluble part gave a pour point reduction of more than 20 0., Whilst the soluble part was inactive with regard to Pennsylvania turbine oil.

A product prepared in exactly the same manned by condensation of 1 mol. of naphthalene and 2 mol. of chlorinated paraflln wax; when added in a quantity of 0.5% to the same Pennsylvania 011, did practically not reduce the pour point. After eliminating the excess of paraflin in a nitrogen current at 250 C. and a pressure of 10 mm., 0.5% gave a pour point reduction of 2 C. 15 grams of the product was separated by means of butanone into 8 grams soluble in bucarbons can also be obtained in a difl'erent manner, as is shown by the following example.

4. 17 grams of picene were stirred during about 12 hours at room temperature with 32- grams of cetene sulphuric acid (obtained by mixing 67 grams of cetene with 30 grams of H2804 of 96% while cooling with ice). Then the product was poured into iced water and extracted with benzene. The benzene extract was subsequeniity washed until neutral and then the benzene was evaporated. 0.5% of the resulting product reduced the pour point of Pennsylvania turbine oil by 5 C.

A product obtained in exactly the same manner from 13 grams of naphthalene and 65 grams of cetene sulphuric acid was inactive with regard to the same Pennsylvania. turbine oil.

The examples given above clearly show thatthe products obtained by condensation of highly condensed aromatic hydrocarbons with high molecular paraflinic hydrocarbons are far more active pour point reducers than those obtained by condensation of the simple aromatic hydrocarbons with high molecular parafiinic hydrocarbons.

Results similar to those described above were also obtained when using instead of Edeleanu extract or naphthalene either substituted highly condensed cyclic hydrocarbons, or untreated cracked residues or the residues polymerized by reheating at cracking temperatures (above 700 F.), and, in some cases, in the presence of knownv ucts of the refined high boiling petroleum distil lates, like paraflin base lubricating oils; it is to be understood, that any petroleum fraction with appreciable content of higher parafllnic hydrocarbons, can be chlorinated and used in preparing the pour point reducing agents of this invention; paraflinic hydrocarbons may be concentrated in such fractions by one of the known methods, such as sulphuric acid treatments, extraction with selective solvents, etc., and, preferably, should boil above 250 0. (A. s. 'r. M),

have an average molecular formula CnHfln-l-Lo 1) and should leave at least 97 unsulfonatable H2SO4. v

A few tenths per cent of the products manufactured by coupling highly condensed aromatic hydrocarbons with higher paraflinic hydrocar- 7 0 residue after being treated with an excess of 98% bons added to, say lubricating oils, is, as a rule, already sufiicient to obtain a pour point reduction of l0-30 C. dependent on the pour point of the oil to be treated. The products are generally applicable to various kinds of hydrocarbon oils, e. g. natural as well as synthetic lubricating oils (manufactured from mineral or tar oils), fuel oils, oil residues, etc. Furthermore the compounds in question can be used in drilling wells, in order to prevent the deposition of well-wax.

I claim as my invention:

1. A process for lowering the pour point of mineral oil, which comprises incorporating therein a small quantity of an alkylated, highly condensed cyclic hydrocarbon having high molecular paraiiinic side chains, and having nuclei containing more than three aromatic or hydrogenated rings.

2. The process according to claim 1 wherein the alkylated, highly condensed hydrocarbons are incorporated in pour point reducing proportions only.

3. A process for lowering the pour point of mineral oil, which comprises incorporating therein less than 1% of the product obtained by the condensation of halogenated high molecular paraflinic hydrocarbons with highly condensed cyclic hydrocarbons selected from the group consisting oi cyclic hydrocarbons having more than three aromatic or hydrogenated rings in their molecules, and concentrated solutions of such polycyclic hydrocarbons obtained by the condensation of extracts obtained inrefining mineral oils containing cyclic hydrocarbons with selective solvents for non-parafllnic hydrocarbons.

4. A process for lowering the pour point of mineral oil, which comprises incorporating therein less than 1% of the product obtained by the condensation of halogenated high molecular parafilnic hydrocarbons with a mixture of pre-condensed cyclic hydrocarbons selected from the group consisting of cyclic hydrocarbons having more than three aromatic or hydrogenated rings in their molecules, and concentrated solutions of such polycyclic hydrocarbons obtained by the condensation of extracts obtained in refining mineral oils containing cyclic hydrocarbons with selective solvents for non-parafilnic hydrocarbons.

5. The process according to claim 4 wherein the mixture of pre-condensed cyclic. hydrocarbons was formed by the condensation treatment of naphthalene in the presence of a catalyst.

6. As a new article of manufacture, a mineral oil containing a small quantity sufiicient to reduce the pour point of said mineral oil or an alkylated, highly condensed cyclic hydrocarbon having high molecular paraflinic side chains, and having nuclei containing more than three aromatic or hydrogenated rings.

7- An improved lubricating oil comprising a blend of a viscous hydrocarbon fraction containing a waxy constituent in proportion suflicient to give an undesirably high pour point and a quantity less than 1% out sufllcient to reduce said pour point of an alkylated highly condensed cyclic hydrocarbonhaving high molecular parafllnic side chains, and having nuclei having more than three aromatic or hydrogenated rings.

8. An improved lubricating oil comprising a blend of a viscous hydrocarbon fraction containing' a solid waxy constituent in proportion suflicient to give an undesirably high pour point, and a quantity less than 1% but suflicient to reduce said pour point of alkylated picene having high molecular parafilnic side chainsof the size of normally solid paraflinic hydrocarbons.

9. An improved lubricating oil comprising a blend of a viscous hydrocarbon fraction containing a solid waxy constituent in proportion sufllcient to give an undesirably high pour point, and a quantity less than 1% but suflicient to reduce said pour point of an alkylated, highly condensed cyclic hydrocarbon having high molecular paraifinic side chains of the size of normally solid parafilnic hydrocarbons, and having nuclei of more than three aromatic or hydrogenated rings obtained by condensing liquid SOs-soluble portion of a mineral oil containing cyclic hydrocarbons in the presence of a catalyst.

' ADRIANUS JOHANNES VAN PESKI. 

